1、查看java的安裝版本
[root@localhost ~]# rpm -qa|grep java
python-javapackages-3.4.1-11.el7.noarch
java-1.8.0-openjdk-headless-1.8.0.111-2.b15.el7_3.x86_64
javapackages-tools-3.4.1-11.el7.noarch
tzdata-java-2016j-1.el7.noarch
2、卸載：
[root@localhost ~]# rpm -e--nodeps python-javapackages-3.4.1-11.el7.noarch
[root@localhost~]# rpm –e --nodepsjava-1.8.0-openjdk-headless-1.8.0.111-2.b15.el7_3.x86_64
[root@localhost ~]# rpm -e--nodeps javapackages-tools-3.4.1-11.el7.noarch
[root@localhost ~]# rpm -e--nodeps tzdata-java-2016j-1.el7.noarch
3、出現下面的畫面表示卸載完成
[root@localhost ~]# rpm -qa-grep| java
-bash: /usr/bin/java: No suchfile or directory
安裝JDK請參考http://blog.csdn.net/hanvding/article/details/53896562